diff options
| -rw-r--r-- | Documentation/rtc.txt | 6 | ||||
| -rw-r--r-- | drivers/rtc/rtc-sysfs.c | 35 |
2 files changed, 40 insertions, 1 deletions
diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt index 8446f1ea1410..ddc366026e00 100644 --- a/Documentation/rtc.txt +++ b/Documentation/rtc.txt @@ -157,6 +157,12 @@ wakealarm: The time at which the clock will generate a system wakeup the epoch by default, or if there's a leading +, seconds in the future, or if there is a leading +=, seconds ahead of the current alarm. +offset: The amount which the rtc clock has been adjusted in firmware. + Visible only if the driver supports clock offset adjustment. + The unit is parts per billion, i.e. The number of clock ticks + which are added to or removed from the rtc's base clock per + billion ticks. A positive value makes a day pass more slowly, + longer, and a negative value makes a day pass more quickly. IOCTL INTERFACE --------------- diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c index 463e286064ab..63b9fb1318c2 100644 --- a/drivers/rtc/rtc-sysfs.c +++ b/drivers/rtc/rtc-sysfs.c @@ -218,6 +218,34 @@ wakealarm_store(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RW(wakealarm); +static ssize_t +offset_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + ssize_t retval; + long offset; + + retval = rtc_read_offset(to_rtc_device(dev), &offset); + if (retval == 0) + retval = sprintf(buf, "%ld\n", offset); + + return retval; +} + +static ssize_t +offset_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t n) +{ + ssize_t retval; + long offset; + + retval = kstrtol(buf, 10, &offset); + if (retval == 0) + retval = rtc_set_offset(to_rtc_device(dev), offset); + + return (retval < 0) ? retval : n; +} +static DEVICE_ATTR_RW(offset); + static struct attribute *rtc_attrs[] = { &dev_attr_name.attr, &dev_attr_date.attr, @@ -226,6 +254,7 @@ static struct attribute *rtc_attrs[] = { &dev_attr_max_user_freq.attr, &dev_attr_hctosys.attr, &dev_attr_wakealarm.attr, + &dev_attr_offset.attr, NULL, }; @@ -249,9 +278,13 @@ static umode_t rtc_attr_is_visible(struct kobject *kobj, struct rtc_device *rtc = to_rtc_device(dev); umode_t mode = attr->mode; - if (attr == &dev_attr_wakealarm.attr) + if (attr == &dev_attr_wakealarm.attr) { if (!rtc_does_wakealarm(rtc)) mode = 0; + } else if (attr == &dev_attr_offset.attr) { + if (!rtc->ops->set_offset) + mode = 0; + } return mode; } |
